Tape Automated Bonding (TAB) is a process that is used to interconnect a chip to a package. The TAB process involves bonding an integrated circuit (IC) device to a patterned metal on a polymer tape which typically consists of copper foil on a polyimide tape. Once the IC device is bonded to the tape the apparatus is commonly referred to as a Tape Carrier Package (TCP).
FIGS. 1A and 1B illustrate a top and side view of a typical prior art TCP 100, respectively. As shown in FIGS. 1A and 1B, the frontside of an integrated circuit device 102 is attached to the polyimide tape 104. The tape 104 is secured within a plastic carrier 106 which provides structural support to the TCP. Bond pads 110 on the frontside of the integrated circuit device are bonded to copper leads 108 formed on the polyimide tape 104. The copper on the polyimide tape 104 is patterned to form the electrically conductive leads 108 which are used for power, ground, and signal distribution between IC device 102 and a substrate, such as a printed circuit board (PCB). Test pads 112 are provided along the outer periphery of TCP 100 to facilitate the electrical testing of IC device 102 before the TCP is shipped to the customer. A plastic encapsulant 126 covering the frontside surface 115 of device 102 provides protection to bond pads 110 and the frontside (active side) surface of the device. Alignment holes 116 in tape 104 facilitate the alignment of test pads 112 with the corresponding electrical interface structure of a test device (not shown).
During the post-manufacture of integrated circuit devices, the devices are subjected to a reliability test called "burn-in" prior to their shipment. The burn-in test is a functional test subjecting an integrated circuit device to a temperature and voltage condition for the purpose of screening out bad devices. The devices attain thermal equilibrium (steady state) when subject to this test. The present invention is aimed at steady state heat dissipation from the surface(s) of an integrated circuit device(s) during functional tests such as burn-in.
During burn-in, the integrated circuit device is housed in a semiconductor package such as a TCP, ball grid array (BGA), pin grid array (PGA), land grid array (LGA), and other packages. The semiconductor package is positioned within a socket that electrically connects the package to a printed circuit board. The printed circuit board is commonly referred to as a "burn-in board" (BIB). The burn-in board includes a multilayer printed circuit board that couples the socket to a test system.
It is important to control the temperature of the integrated circuit device since excessive temperatures may affect the performance of the circuit and cause permanent degradation of the device. In addition, it is desirable to hold the temperature of the integrated circuit device at a relatively constant temperature throughout the test.
The traditional method for cooling integrated devices during burn-in has been through convection heat transfer. Using this method, heat is dissipated from the integrated circuit through the outer surfaces of the device into still or moving air. As the integration level (i.e., the number of transistors per device) of integrated circuits increases, or the power requirements, or the operating speed of these integrated circuits increases, the amount of heat generated by these devices increases to a point where conventional convection solutions are inadequate. This poses a particular problem when testing integrated circuit devices housed within TCPs or other packages having a low thermal mass (i.e. LGAs). If the integrated circuit device is not adequately cooled during the test, and is permitted to rise significantly above a designated test temperature, the device may suffer permanent degradation. In such instances, the integrated circuit must be discarded.
Thus, what is needed is an apparatus for controlling the temperature of an integrated circuit device during burn-in.